I pretty sure the jigging was their Plan B since there were not many suspended fish to catch on the troll, they reverted to tactics that are the prime tactic on inland lakes and rivers which is to work the bottom with jigs. These guys that are skilled at catching walleye inland have an advantage over those of us that rely on suspended fish and trolling when the bites tough (in my opinion). I think the most useful piece of information is you saw some guys managing to entice the negative bottom oriented fish to bite and that IS good to know and take note of on those days where you can’t get a program going but see a lot of fish near the bottom. Something else to try on a tough day.